CD179: Deep-sea biology of the Portguese canyons


Daily diary

Monday 24 April 2006

Raquel writes:

"Well, today started with bitter disappointment for Veerle and I, the two geologists onboard, because we had been promised a piston core for this morning. However, the weather proved to be against us and fancied giving us a choppy sea and strong winds rather than calm corable* conditions. I was doubly disappointed because I am on the night watch and hence had to make do with 5 hours of sleep in order to get up early for the proposed time at which the piston core would have arrived on deck. To add insult to injury, the bad weather made it unpleasant for sunbathing! So all in all, I was not at all impressed with how the day was panning out for me by midday.

Never mind. For everyone else, it was a successful day for SAPS and CTD. Photo 1 shows the deployment of the lander containing the CTD and SAPS equipment. We (and by we I really mean Terry, aided by Sarah and John) obtained several CTD temperature and salinity profiles of the water column (Photo 2).

2. Terry keeps a close eye on CTD operations

1. Launch of the CTD, which measures conductivity, temperature and depth in the water column

SAPS did lots of water pumping and filtering at the sea bed. This filtering is to collect all the organic green goo (there’s no other description for it, see Photo 3!) that floats around at the sea bottom, and is made up of zooplankton, dead organisms and their faeces. Photo 4 shows the pump with Veerle for scale. This organic material will then be studied by Kostas, who couldn’t come with us on the cruise (but who was present on last year's D297 cruise), to get an insight into the lowest but possibly most important members of the marine food chain.

3. Green 'goo' from the seabed

4. Veerle deals with the SAP

At midnight we attempted another SHRIMP run. It was running beautifully to start with, undergoing a soft landing thanks to the careful manoeuvres of Mr Winch Man, and showing us some beautiful corals and large oysters growing on some rocky ledges. However, after only 15 minutes of recording, SHRIMP underwent a power failure and had to be hauled up to be fixed on deck. But this proved not to be completely unsuccessful, as some underwater turbulence caused by the contact between SHRIMP and the above mentioned rocky ledges, meant it brought up some samples of this maerl (concreted shells) for the biologists to have a closer look at (see Photo 5).

5. Maerl - lots of shells concreted together to form a rocky substance

Luckily, I have just been told that the weather might be improving for Wednesday, so hopefully we’ll be able to do some piston coring then – fingers crossed!"

* Corable (a.) = Marine geological jargon meaning suitable conditions for coring. Not to be confused with a coracle (n.) = a Welsh round-boat, similar to a canoe, and propelled by a single paddle.

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April 2006
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